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sábado, 3 de março de 2012

To efficiently absorb UV light and, at the same time, keep skin lotions transparent, manufacturers of sunscreens often use active UV absorbers (zinc oxide and titanium dioxide) in the form of nanoparticles.

There are widespread doubts about the safety of such nanoparticles in sunscreens: can they be hazardous?

In Australia, the country with the strongest sunlight exposure and the highest skin cancer rates, the topic is discussed most intensively. According to a study by theAustralian Government from February 2012, 17 % of Australians were convinced that “not using sunscreen at all is less risky to my health than using sunscreens that include nanoparticles”.

Experts, however, are warning against too much reservation. After all, nanoparticles are purposely used in sunscreens to optimize their UV protection. Paul Wright, Australian toxicology professor at RMIT University, recently summarized results in an online interview:

“Toxicity from zinc oxide particles was only seen at extremely high doses that would not be achieved from sunscreen use. […] It is important to weigh up the known risk of skin damage from excessive UV exposure, with the diminishing perceived risk of using nano sunscreens.”

One year ago, the American Environmental Working Group (EWG) had already published sunscreen test results that compared nanoparticle-based products with those based on chemicals. The study also explicitly considered public reservations. Mother Nature Network (MNN) summarized them as follows:

“While there is some concern over the safety of nanoparticles in mineral sunscreens, the EWG believes that they’re safer than chemicals like oxybenzone, octyl methoxycinnamate (OMC), 4-Methylbenzlidene camphor (4-MCB) and padimate O.”

In Europe, the NANO-DERM project investigated a potential skin penetration of titanium dioxide nanoparticles. In their final report, the participating scientists concluded:

“Summing up, we do not expect any health effects for the topical application of sunscreens containing TiO2 nanoparticles (especially when coated) on healthy skin which are related to the particulate state.”

Everybody will need to weigh up by himself: can potential risks that have never been affirmed in toxicity studies legitimate an increased risk of skin cancer?
If so, we ought to use parasols.